Researchers at a US university have found the brains of obese children function differently from those children of healthy weight, and suggest that diet and exercise may not be enough to restore their normal weight.

The study conducted at the Vanderbilt University Medical Centre in Tennessee said mindfulness -- a practice used as a therapeutic technique to focus awareness -- should be studied as a way to encourage healthy eating and weight loss in children.

Using MRI scan, the researchers found that unhealthy eating behaviours and obesity could reflect an imbalance in the functional connectivity of brain areas associated with response inhibition, impulsivity and reward.

The practice of mindfulness can increase response inhibition and decrease impulsivity.

Although mindfulness has had mixed results when used for weight loss and weight control among adults, reflecting "the extreme tenaciousness of adult obesity," as well as age-related loss of brain plasticity, the study supports the importance of early identification of children at risk for obesity, and the need to develop novel methods to treat and prevent it, the researchers said.

The study findings were published on January 21 in the journal Heliyon.